Method of making bags



March 12, 1940. T, M, VERY 2,193,756

METHOD OF" MAKING BAGS Original Filed May 12, 1938 2 SheetsSheet 1 2%:fines-RY March 12, T M AVERY v 2,193,756

METHOD OF MAKING BAGS Original Filed May 12, 1938 2 Sheets-Sheet? grwmtob z 7kua/f 144R)? Patented Mar. 12, 1940 PATENT OFFICE 2.19s,75s METHODOF MAKINGnAea True M. Avery, Glensllalls, i58

assigfror" to Union Bag & Paper Corporatiem'llirdsonfalls, N. Y., acorporation of New Jersey Original application May 12, 195:8, Serial No.

207,620. Divided and this application October 14, 1938, Serial N0.235,073

'- 4 Claims.

The present invention relates to improvements in the manufacture of bagsof thekind composed of paper, Cellophane or other flexible material ,andadapted to contain goods or commodities of various kinds, and it relatesmore particularly to the manufacture of bags of the so-called satchelbottom type, wherein the bottom is closed by flaps formed by foldinginwardly the edges and then folding and pasting portions of the sides ofthe bag onto the first folded flaps.

In making bags of this type, it has been the common practice heretoforeto form slits in the side portions of the bag which are to constitutethe bottom closing flaps to afford increased areas fortthepasting ofthese flaps ,down upon the previously foldedflaps, but such slitting ofthe bag presents the disadvantages that the flaps have a. tendency totear beyond the slits when the end-of. the bag tube is opened during theprocess of forming the bag bottom, and in the finished bag the weight ofthe material therein often causes the bottom flaps to tear beyondtheslits,

resulting in leakage of the contents of the bag.

vThe primary object of. the present invention is 25 to provide a noveland improved method of making a bag which avoids such disadvantages, it

providing the bottom closing flaps of the bag with tabs or ears whichproject therefrom and afford increased or supplemental areas for thepasting and securing of such flaps to the previously folded bottomflaps, thereby serving to distribute the loadof the contents of the bagover a larger area of the bottom thereof and thus strengthening andavoiding tearing of the bag bottom, these tabs or ears being formedprior to-the folding of the bottom flaps and avoiding any. tendency ofthe flap forming portions of the bag to tear during.

the bottom forming operation as occurs when the flap forming portionsare slitted, as heretofore.

4,0 These featureszof the presentinvention are particularly advantageouswhen the bags are made I Fig. 2 is a view similar to Fig. 1 but showingone edge of the strip folded; Fig. 3 shows the strip completely foldedto form a bag tube;

Fig. 4 shows a bag length cut from the bag tube;

Fig. 5 shows an end of the tubular bag length after the same has beenopened'to fold the side edges inwardly and thus form two of the bottomclosing flaps;

Fig. 6' is a view similar to Fig. 5 but showing the closing flap at oneside of the bag folded onto the previously folded bottom flaps;

Fig. 7 is a view of the completed bag, partlyin section and partlybroken away, the closing flap at thefotherside of the bag being shownfolded and pasted onto thepreviously folded flaps;

Fig. 8 is a detail section taken on the line 88 in Fig. 5; I Fig. 9 is adetail section taken on the line 9-9 in Fig. 6; and

Fig. 10 is a detail section taken on the line i0l0 in Fig. 7. I

The method according to the present invention is applicable generally tothe manufacture of bags k having either a single wall or thickness ortwo or more walls or thicknesses, it being shown'for example in thepresent instance as appliedto the manufacture of .a bag of the so-calledduplex type'having two walls or thicknesses.

In carrying out the invention as shown in the present instance, the bagsmay-be formed from a strip composed of two sheets or webs I. and

2 of paper, Cellophane" ,orother suitable flexible .35 material whichare placed one upon the other in offset or staggered relation asv shownin Fig. 1. Before superposing, the sheets transverse rows of spots ofadhesive 3 and 4 are applied to one of the sheets adjacent to the lines,indicated at 5, 40 on which the bag tube is tobe severed in forming thebag lengths',these spots of adhesive serving. to' unite ,the sheets.in'the regions of the-"finished bag bottom and fthebag mouthl, Eachsection of the strip is formed, adjacent to the line, of

severance 5 w ith apair Tof tabs orears iyvhich are preferablysemi-circular in. form. and may be produced by punching 'semiicirciil arcuts through those portions of both" of the" sheets which ad.- join theportions thereof whieh are to form'the finalbottorn clt'isin'gflap, thebases of these semicircularF tabs'or ears lying-on divergent lines "Iwhich "represent" the folded marginaledges of the final bottomclosing'flap." The pastespots 3 are so located that certain of thesepaste spots will lie at the bases of these tabs or ears and will therebysecure together the tabs or ears on the two sheets. The bag strip, whilein flat or web form, may also be punched with holes 8 which extendthrough both sheets and extend to opposite sides of the lines 5 on whichthe bag tube is severed, a portion of each of these holes forming athumb hole 9 at the mouth of the bag, and. the other portion of each ofeach of these holes forming a cutaway portion ID on one of the bottomclosing flaps.

The bags may be made rapidly on a bag machine of conventional formhaving a former to which the bag strip is fed, and having folders forfolding the longitudinal edges of the strip inwardly on the line I I asshown in Fig. 2 and for folding the opposite longitudinal margin of thestrip inwardly on the line l2 to bring lines of adhesive I3 and I4previously applied to the sheets I and 2, onto the inwardly foldedportions along the opposite margin of the strip, thus forming the stripinto a bag tube as shown in Fig. 3, the lines of adhesive l3 and I4forming the longitudinal seams of the bag. The bag tube thus formed isthen severed, on the lines 5, to form a bag section as shown in Fig. 4.

The end of each bag length which is to constitute thebottom of the bagis then opened into the form of a diamond fold, which may beaccomplished by the well known bottoming mechanism of a bag machine ofconventional type. This "diamond fold is formed by pulling the side ofthe bag provided with the cutaway portion It) and folding it against thebody of the bag along the fold line I5, in consequence of which the edgeportions of the bag are drawn inwardly to form the bottom flaps I6. Thedrawing inwardly of the flaps I6 forms diagonal fold lines I betweenthem and the opposite sides of the bag, and since the fold lines 'Iextend across the bases of the tabs or ears 6 which are cut from theseportions of the bag strip which form the flaps IS, the tabs or ears 6will remain unfolded and will project beyond the fold lines I, as shownin Fig. 5.

The portion of the bag bottom provided with the cutaway portion I0 .isthen supplied with spots of adhesive l8, and a spot of adhesive I 8 isapplied through the cutaway portion II) to this portion of the bagbottom, and spots of adhesive 2| are applied to the tabs or ears 6 and aspot of adhesive 2| is applied between the inner edges of the infoldedflaps I6 to the outer portion of the closing flap 22. The extremity ofthe portion of the bag bottom having the cutaway portion is then foldedon the fold line I9 to form a bottom closing flap 2!! which is pastedonto the flaps I6, as shown in Fig. 6, after which flap 22 is folded onthe fold line 23 onto the previously folded flaps I6 and as shown inFig. 7, so that the tabs or cars 6 which overlie portions of the flapsI6 and the flap 20 as well as the closing flap 22 will be securelypasted to the underlying previously folded flaps by the paste spots 2|and 2| thus completing the bag bottom. By applying a spot of paste I8through the cutaway portion In onto the portion of the flap 20 which isexposed through this cutaway portion, the outer portion of this flap issecurely pasted to the underlying flaps I6.

The tabs orv ears 6 provided on the bottom closing flap, when suppliedwith the paste spots 2| and pressed against the underlying or previouslyfolded flaps l6, securely seal or secure the outer portion of the flap22 to the flaps I6 and the spot of paste 2| applied to the flap 2 nearits apex or extremity securely seals the outer portion of this flap tothe previously folded flap 20.

In applying the invention to the manufacture of a duplex bag, as shownin the present instance, the paste spot I8 applied through the cutawayportion Ill to the outer portion of the flap 20 will secure both outerplies of this flap to the flaps I6 since the outermost ply of the flap20 is secured to the adjacent inner ply thereof by the paste spots 3,and the paste spots 2| and 2|- applied respectively to the tabs or ears6 and to the outer portion of the flap lying between the inner edges ofthe flaps I6 will secure both outer plies of the flap 2 to the flaps I6and 20 respectively, since the outermost ply of the flap 22 is securedto the adjacent inner ply thereof by the paste spots 3.

While the invention is shown applied to the manufacture of a bag of theduplex" type comprising inner and outer walls or plies, obviously theinvention is equally applicable to the manufacture of bags having asingle wall'or ply which can be made by the same method hereinbeforedescribed but from a single sheet instead of two sheets, in which eventthe paste spot I8 applied through the cutaway portion III to the flap 20will directly seal or secure the outer wall or ply of this flap to theflaps I6, and the paste spots 2| and 2| applied respectively to the tabsor ears 6 and between the inner edges of the flaps I6 to the outerportion of the flap 22 will directly seal or secure the outer wall ofthe flap 22 to the flaps I6 and 20 respectively.

Although the paste spots 2| applied to the tabs and the paste spots 3between the sheets adjacent to the bases of the tabs in a duplex" bagare preferably relatively small as shown, these paste spots will spread,when pressure is applied incident to the pasting together of the bottomflaps, suificiently to cover ample areas of the tabs to firmly securethem, thereby avoiding objectionable squeezing of excess paste frombetween the flaps.

By providing the tabs or cars 6 on the bottom closing flap 22, this flapis secured over a larger extent of its area to the previously foldedflaps than heretofore, thereby strengthening the bag bottom anddistributing the stress of the load in the bag over a larger area of thebag bottom, thus enabling the bag bottom to effectively withstand anytendency to tear under the load, as in bags of the satchel bottom typehaving slits in their bottom flaps.

Moreover, by providing these tabs or cars instead of slits as heretoforeemployed, the stress applied in opening the bottom of the bag into adiamond fold during the bottom forming operation will not tear the bagbottom, as fre quently occurs in the manufacture of bags of the satchelbottom type having slltted bottom closing flaps.

The method according to the present invention may be employed tomanufacture bags on bag machines of conventional and well known formeconomically and with the same speed and facility as ordinary bags.

I claim as my invention:

l. The method of making satchel bottom bags which comprises cuttingadjacently located tabs and an aperture offset laterally therefrom in astrip of material, forming the strip into a tube and thereby bringingsaid tabs and aperture into positions on one side of the tube, forming adiamond fold at one end of the tube along fcld lines some of whichintersect the bases of said tabs and others of which converge towardsaid aperture, thereby providing bottom flaps connected by diagonal foldlines and causing-the tabs to project unfolded from the diagonal foldlines of one of the flaps and exposing a portion of the outer ply of theother flap through said aperture, applying adhesive to said tabs and t0;;ube on a transverse line adjacent to said tabs and intersecting saidaperture, forming a diamond fold at one end of the bag length, therebyfolding the edges of the bag length inwardly to form bottom flapsconnected by diagonal fold lines two of which extend past the bases ofsaid tabs and two of which fold lines converge toward said aperture,thereby leaving said tabs unfolded and projecting from said fold linesof one of the flaps and exposing a portion of the outer ply of the otherflap through said aperture, applying adhesive to said tabs and flaps andto said exposedmortion of said outer ply, and folding said flaps andtabs to adhesively secure them.

3. The method of making bags which comprises forming tabs in a portionof a strip of material which is to form one side of a bag tube, thenforming the strip into a tube and thereby bringing said tabs to saidside of the tube in positions spaced equidistantly laterally of thelongitudinal center thereof, then severing the tube on a transverse lineadjacent to but spaced outwardly from said tabs to form abag length,then folding an end of the bag length on lines which substantiallyintersect the bases of said tabs, thereby forming bottom closing flapsand leaving said tabs unfolded and projecting from the fold lines of oneof the flaps, and subsequently applying adhesive to said tabs, andfolding said tabs and the flap from which they project onto underlyingflaps.

4. The method of making bags which comprises cutting adjacently locatedsubstantially semi-circular divergently extending tabs in a strip ofmaterial at one side of its longitudinal center, then forming the stripinto a tube and thereby bringing said tabs into positions spacedlaterally from the longitudinal center of one side ofthe tube, thensevering the tube on a transverse line adjacent to but spaced outwardlyfrom said tabs to form a bag length, then foldingan end of the tube toform bottom closing flaps connected by diagonal fold lines some of whichsubstantially intersect the bases of said tabs, thereby causing saidtabs to remain unfolded and to project from the fold lines of one of theflaps, and subsequently applying adhesive to said tabs, and folding theflap and the tabs projecting therefrom onto and 'adl esively securingthem to underlying flaps.

\ TRUE M. AVERY.

